/**
 * Author : wang885298.
 * Date   : 2017/9/23.
 * File   : onShow.
 */
function closeBomb () {
  var bomb = document.getElementById('bomb')
  if (bomb.style.display === 'block') {
    bomb.style.display = 'none';
  } else {
    bomb.style.display = 'block';
  }
}